Method of erecting parallel wire strands in bridge saddles

ABSTRACT

PARALLEL WIRE STRANDS ARE POSITIONED IN A BRIDGE SADDLE BY COMPACTING THE STRANDS INTO A RECTANGULAR CROSS SECTION AND APPLYING U-SHAPED FORMS TO THE STRAND AT SPACED LOCATIONS ALONG THE PORTION OF THE STRAND WHICH IS TO BE SUPPORTED IN THE SADDLE. THE SHAPED STRANDS ARE THEN PLACED SIDE BY SIDE IN THE SADDLE IN LAYERS AND AS EACH LAYER IS COMPLETED THE U-SHAPED FORMS ARE REMOVED.

Dec. 14, 1971 J. R. BELL ETAL 3,626,534

METHOD OF ERECTING PARALLEL WIRE STRANDS IN BRIDGE SADDLES Filed April16, 1969 e R W In 0 w m m J J l N VE N TORS United States Patent Olhce3,626,534 METHOD OF ERECTING PARALLEL WIRE STRANDS IN BRIDGE SADDLESJoseph R. Bell, Warwick, R.I., and John E. Windsor, Bristol, Md.,assignors to Bethlehem Steel Corporation Filed Apr. 16, 1969, Ser. No.864,231 (Filed under Rule 47(a) and 35 U.S.C. 116) Int. Cl. E01d 11/00US. Cl. 14-22 3 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THEINVENTION This invention relates to the erection of suspension bridgecables and more particularly to the placement of parallel wiresuspension cables in bridge saddles.

The main cables of suspension bridges are usually composed of a largenumber of steel wires arranged parallel to each other. Traditionally theindividual wires have been separately erected by spinning back and forthbetween the cable anchorages.

The individual wires are laid in the bridge saddles as they are carriedacross the span during spinning. These wires are then temporarilygathered into strands and then compacted together to form the finalbridge cables.

A recent development described in assignees copending application Ser.No. 575,038, filed Aug. 25, 1966 and now Pat. No. 3,526,570, has madepossible the shop fabrication of long hexagonal parallel wire strands.These hexagonal parallel wire stands are transported after fabricationto the bridge site and are erected upon the bridge by pulling themacross the bridge span. Usually the parallel wire strands are pulledacross the bridge on rollers and are then lifted from the rollers by ahoist and deposited in the saddles in a predetermined arrangement.

It is very important that the strands be compactly placed within thesaddles with a minimum of voids between the wires. Previous practicewith shop fabricated strands has been to place the strands in horizontallayers within the saddle with sheet metal separators between the layers.The hexagonal strands were slid into position across the smoothseparators and compacted together into layers of wires by hydraulic orother compression means exerting both horizontal and vertical pressureon the strands. This treatment involved considerable stress upon thehexagonal strands to compress them into uniform layers and the sheetseparators added voids to the completed cable within the saddles.

SUMMARY OF THE INVENTION The foregoing difficulties have been obviatedby the present invention which compacts each individual hexagonal strandinto a rectangular configuration prior to placing it in the saddle.Rectangular or U-shaped forms are placed at intervals over the portionof the strand which is to rest in the saddle to shape and maintain thestrand in a regular rectangular shape. Securing means are then placedaround the forms to retain the wires temporarily within the forms andthe shaped, or formed, strand is placed within the saddle in its finalposition with the open end of the form facing downwardly. After eachlayer of strands is placed in the saddle the securing means is re-3,626,534 Patented Dec. 14, 1971 leased and the forms are withdrawnleaving a uniform layer of compactly arranged rectangular strands withinthe saddle. A second layer of strands is then placed upon the first inthe same manner and this procedure is repeated until all the wires ofthe suspension cable have been placed in the saddle.

This method of positioning and compacting the strands is much faster andmore accurate than previous methods and has the additional advantagethat the height of each layer of strands making up the cable can beeasily varied by using form members of different dimensions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic elevationshowing a suspension bridge saddle in which shop fabricated parallelwire strands are being placed.

FIG. 2 is a cross-sectional elevation taken along the line 22 of FIG. 1.

FIG. 3 is a schematic plan perspective of parallel wire strands beingplaced in a brige saddle according to the present invention.

FIG. 4 is a perspective view of form members being applied to a parallelwire strand.

FIG. 5 is a perspective view of a form member.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1, 2 and 3 show shopfabricated parallel wire strand 11 being placed within the trough 13 ofa suspension bridge saddle 15. Each originally hexagonal strand 11 ispulled across the bridge span and past saddle 15 on rollers 17. Afterthe strand is correctly positioned longitudinally with respect to thebridge span, the strand in the area of the saddle is compacted to anelongated rectangu-- lar shape by means of the fiat adjustable jaws 21and 23 of clamp 25 as seen in FIG. 4. U-shaped form members 19 are thenplaced over the strand as shown. Other suitable means may be used tocompact the strand prior to the application of members 19 and ifnecessary the form members can be forced over the strand by the use ofwooden mallets or the like.

After the strand is shaped and the form members applied as shown in FIG.4 a strap or band 27 or other suitable securing means is positionedabout the form mem bers 19 to temporarily secure the shaped strandwithin the form member. The shaped strand is then transferred from therollers 17 by any suitable transfer means such as derrick 29 and placedin the trough 13 of saddle 15 in the position which it is finally tooccupy as shown in FIG. 3. The various strands of each layer of strandsin the saddle trough 13 are placed tightly together as shown. The shapedstrands are placed with the forming members 19 open end downwardly sothat all the forming members may be easily removed. After each layer ofstrands is completed the straps 27 or other securing devices arereleased and forming members 19 removed. As the forming members 19 areremoved, the rectangular bundle of Wires spreads out slightly to take upthe space occupied by the forms leaving a compact even layer of wiresWithin the saddle trough. Subsequent layers of strands are easilyerected in the same manner upon the initial layers as shown in FIG. 2until a predetermined number of layers of wires have been formed in thesaddle. After inated when erecting strand according to the presentinvention.

3 By the present invention the time necessary for the placement ofparallel wire strands in bridge saddles is very materially decreased andthe compactness and efiiciency of the suspension strand within thesaddle is materially increased.

We claim:

1. A method for erecting shop fabricated hexagonal parallel wire strandsin a bridge saddle comprising:

(a) shaping a plurality of hexagonal parallel wire strands intoindividual rectangular configurations of equal height Within strandforming means,

(b) securing said strands with strand retaining means to maintain theirrectangular configuration,

(c) closely positioning a plurality of said strands within the trough ofa bridge saddle to form a substantially planar layer of said strands,

(d) removing the retaining means from each of said strands within thesaddle leaving a uniform planar layer of suspension wires,

(e) repeating steps (a) through ((1) until a predetermined number oflayers of wires have been placed in the trough of the saddle.

2. The method for erecting shop fabricated hexagonal parallel wirestrands in a bridge saddle according to claim 1 wherein each of thestrands is inserted into a U-shaped forming means to form it and issecured therein with a securing means to retain the shape of said strandand wherein the U-shaped forming means are faced downwardly when thestrands are placed within the trough of the saddle to facilitate theirremoval.

3. The method of erecting shop fabricated hexagonal parallel wire strandin a bridge saddle according to claim 2 wherein said strands arecompacted into an elongated rectangular form prior to placement in saidforming means by the use of clamping means having flat movable jawsadapted to force the wires of said strands into a compact rectangularconfiguration to facilitate the placement of the forming means over thestrand.

References Cited UNITED STATES PATENTS 2,118,187 5/1938 Fine 14-22 JACOBL. NACKENOFF, Primary Examiner

